Well, like we discussed before; a sea-level value will almost always be negative for our purposes but it could be positive. We want to measure the relative change in elevation from the base of the give structure to the MSL. Assuming that measuring upwards is positive, then downwards is negative. However, if the structure's base were to be below MSL, then we would show a positive value. I can think of a few instances where this might occur, namely: around the Dead Sea, in Holland, or a submerged/marine/offshore structure.
I'm just thinking that showing tip elevations as part of the official height list is wrong because we are showing heights relative to base only. While elevations and heights may appear to be the same thing, they are not. If they do get mixed together, it will lead to incorrect "pinnacle" rankings.
all that is really needed is a seperate data-field devoted specifically for recording the difference between our local datum (base of structure) and the global datum (mean sea level, MSL). With that information, the tip elevation can be calculated if need be by adding the structure Height to it's base elevation w.r.t. MSL.
Just a thougt